The present invention pertains to an assembly and method for protecting pipes. More specifically, the present invention pertains to a pipe protection arrangement in which a casement sleeve is placed around a pipe to be protected and then the outer ends of the casement sleeve are sealed against the pipe. Furthermore, the casement sleeve is spaced from the outer circumferential surface of the pipe such that an annular casement cavity is formed therebetween and the present invention provides means for injecting an anti-corrosion compound into this casement cavity.
Cross country pipelines must frequently pass beneath roads and railway beds. To assure adequate protection of these pipelines from damage due to vibration and/or crushing, the use of protective casement sleeves are often required by local regulations. The protective casement sleeves are designed to be sufficiently large to insulate the pipeline from the potential vibration and/or crushing damage.
A problem that arises with the casement configuration is corrosion. Many factors may contribute to this corrosion. Some factors include runoff from the overlying roadbed, runoff chemicals from surrounding farmlands, the nature of the soil, or a galvanic action between the pipeline and the casement itself.
Previous methods for preventing corrosion include a variety of techniques. In one such technique, zinc would be coated on the outside of the pipe and/or the inside of the casement sleeve. This method proved unsatisfactory since the zinc coating would be corroded away leaving the base pipe and/or casement sleeve again susceptible to corrosion damage. In another technique, anode cables would be buried in the ground adjacent to the pipe and electrically connected to the casement sleeve. A cathode line would also be connected to the pipe. Since the anode has a higher potential to corrode, pipe corrosion could be minimized. A further technique includes providing a coating of paint on the members to be protected. As with the zinc coating discussed above, the paint coating provides only temporary protection. None of these techniques have provided satisfactory corrosion protection in all cases.